RVHS H1 Chemistry P2 QP 2024

River Valley High School 8873/02/PRELIMS/24 2024 Preliminary Examination [Turn over RIVER VALLEY HIGH SCHOOL JC 2 PRELIMINARY EXAMINATION CANDIDATE NAME CLASS 2 3 J CENTRE NUMBER S INDEX NUMBER H1 CHEMISTRY 8873/02 Paper 2 Structured Questions 9 September 2024 2 hours Candidates answer on the Question Paper. Additional Materials: Data Booklet READ THESE INSTRUCTIONS FIRST Write your Centre number, index number, class and name on all the work that you hand in. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. DO NOT WRITE IN ANY BARCODES. Section A Answer all the questions. Section B Answer one question. The use of an approved scientific calculator is expected, where appropriate. A Data Booklet is provided. The number of marks is given in brackets [ ] at the end of each question or part question. For Examiner’s Use Question Number 1 2 3 4 5 6 7 8 Marks 9 16 7 5 9 14 20 20 significant figures units Total 80 This document consists of 25 printed pages and 3 blank pages.

2 River Valley High School 8873/02/PRELIMS/24 2024 Preliminary Examination 1 Ammonium sulfite can be prepared by the reaction of ammonia with sulfur dioxide in aqueous solution. 2NH3 + SO2 + H2O → (NH4)2SO3 (a) Draw a ‘dot-and-cross’ diagram to show the bonding in ammonium sulfite. [2] (b) State and explain the shape and bond angle in sulfite anion, SO32−. Shape: ……………………………………………………………………………….. Bond angle: …………………………………………………………………………. Explanation: ………………………………………………………………………..... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… [3] (c) Explain how a dative bond is formed in NH4+. ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… [1] (d) Explain, in terms of structure and bonding, if ammonium sulfite or ammonia has a higher boiling point. ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… [3] [Total: 9]

3 River Valley High School 8873/02/PRELIMS/24 2024 Preliminary Examination [Turn over 2 Calcium chloride is used in temperate countries to prevent ice formation. (a) Using an equation, define the lattice energy of calcium chloride, CaCl2. ………………………………………………………………………………………... [1] (b) Use the data from the Data Booklet , explain how the magnitude of lattice energy of calcium chloride might compare to that of magnesium chloride. ………………………………………………………………………………………... ………………………………………………………………………………………... ………………………………………………………………………………………... ……………………………………………………………………………………....... [2] (c) Like magnesium chloride, a solution of calcium chloride is of pH 6.5. With the aid of a suitable equation, explain this observation. ………………………………………………………………………………………... ………………………………………………………………………………………... ………………………………………………………………………………………... ……………………………………………………………………………………....... [2]

4 River Valley High School 8873/02/PRELIMS/24 2024 Preliminary Examination (d) A solution of calcium chloride can be formed from reacting solid calcium carbonate with hydrochloric acid. CaCO3(s) + 2HCl(aq) → CaCl2(aq) + CO2(g) + H2O(l) Hr = x kJ mol−1 When 11.375 g of calcium carbonate is reacted with 250 cm3 of 2.00 mol dm−3 hydrochloric acid , the temperature of the resultant solution increased by 1.58 C. Assuming that 4.2 J of heat is required to raise the temperature of 1.0 cm3 of the solution by 1.0 C, calculate the value of x. [3] (e) The rate of reaction between CaCO3(s) and HC l(aq) can be measured by monitoring the mass of the reaction mixture over time. An experiment was carried out where 11. 375 g of calcium carbonate is reacted with 250 cm3 of 2.00 mol dm−3 HCl(aq) using the following setup: (i) Suggest the purpose of the cotton wool plug. ………………………………………………………………………………… ………………………………………………………………………………… [1]

5 River Valley High School 8873/02/PRELIMS/24 2024 Preliminary Examination [Turn over (ii) Show that the maximum mass loss is expected to be 5.00 g. [1] (iii) Given that the reaction is 1 st order with respect to HCl and 0 th order with respect to CaCO3, write the rate equation for the reaction. ………………………………………………………………………………… [1] (iv) Hence, sketch the expected mass loss over time on the given axis. Indicate the 1st and 2nd half-lives with their corresponding mass loss on your graph. [2]

6 River Valley High School 8873/02/PRELIMS/24 2024 Preliminary Examination (v) With the aid of a Boltzmann distribution curve, explain how the rate of this reaction would be affected by an increase in temperature. ………………………………………………………………………………… ………………………………………………………………………………… ………………………………………………………………………………… ………………………………………………………………………………… ………………………………………………………………………………… ………………………………………………………………………………… [2] (vi) Sketch on the same graph as (e)(iv), the expected mass loss over time for a reaction at a higher temperature. [1] [Total: 16]

7 River Valley High School 8873/02/PRELIMS/24 2024 Preliminary Examination [Turn over BLANK PAGE

8 River Valley High School 8873/02/PRELIMS/24 2024 Preliminary Examination 3 In Formula 1® (F1) racing, where winning the race is dependent on the components of the car, nanocomposites can play an important role. Hence, the Fédération Internationale de l'Automobile (FIA) sets its own guidelines to restrict the use of nanotubes and nanofiber composites in F1 racing sport. (a) Nanotubes are classified as nanomaterials. Define what is meant by nanomaterial. ………………………………………………………………………………………... ………………………………………………………………………………………... ………………………………………………………………………………………... [1] (b) Carbon nanotube (CNT) has a similar structure to graphene. State the property of CNT which can add stiffness in car tyres. Explain why this is so. ………………………………………………………………………………………... ………………………………………………………………………………………... ………………………………………………………………………………………... ………………………………………………………………………………………... [2] (c) Though CNT can enhance the property of a material, it is not used as a coating on the surface of shatterproof windows of the racing cars. Suggest a reason for this. ………………………………………………………………………………………... ………………………………………………………………………………………... ………………………………………………………………………………………... [1] (d) During a race, high static charge accumulation in the car tyre can be a safety hazard at fuelling pit stops. Suggest how CNT in tyres can prevent this. ………………………………………………………………………………………... ………………………………………………………………………………………... ………………………………………………………………………………………... [1]

9 River Valley High School 8873/02/PRELIMS/24 2024 Preliminary Examination [Turn over (e) ‘Armchair’ and ‘zigzag’ are the names of two types of CNT. They are named according to the structures of the nanotubes. Outline the armchair and zigzag shapes on the structures and name the structures. structures names [2] [Total: 7]

10 River Valley High School 8873/02/PRELIMS/24 2024 Preliminary Examination 4 Study the reaction scheme below carefully. (a) State the reagents and conditions needed for reaction 1 and 2. Reaction 1: ………………………………………………………………………… Reaction 2: ………………………………………………………………………… [2] (b) Give the displayed formula of compound A. [1] (c) Give the condensed structural formula o